class_docstr: Base class for DataFlow that proxies another.
  Every method is proxied to ``self.ds`` unless overriden by a subclass.
code: def reset_state(self):
      self.ds.reset_state()
  
imports: import threading
  from abc import ABCMeta, abstractmethod
  import six
  from ..utils.utils import get_rng
label_desc: Use image node_id 2 for calling the ProxyDataFlow obj's underlying member method code with example usage: obj.reset_state() without return types